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VORTEX INDUCED VIBRATIONs AQUATIC CLEAN ENERGY CONVERTER - VIVACE
Shaz muhammad r
Mes COLLEGE OF ENGG:
• The Tacoma narrows bridge incident• Vortex induced vibration• How a fish propels itself in water• The VIVACE• How the vivace works• Why vivace• High utilization expected for vivace• Salient features of vivace• Advantages • References
TOPICS COVERED
The tacoma narrows bridge incident (1940)
November 7, 1940, at 11:00 am (Pacific time)
VORTEX INDUCED VIBRATIONS
• (VIV) are motions induced on bodies facing an external flow by periodical irregularities on this flow.
• They are experienced by any unstable cylindrical objects which may be small car antennas or 120 foot diameter platforms used in off-shore engineering
• Vortex Induced Vibrations (VIV) results from vortices forming and shedding on the downstream side of a bluff body in a current.
• If the frequency of vortex shedding matches the resonance frequency of the structure, the structure will begin to resonate and the structure's movement can become self-sustaining.
• Real fluids always present some viscosity.• Boundary layer will form and thus the flow around
the cylinder will be slowed down while in contact with its surface.
• At some point this boundary layers separate from the body due to its excessive curvature.
• Vortices are then formed changing the pressure distribution along the surface.
• When the vortices are not formed symmetrically around the body, different lift forces develop on either side of the body, thus leading to motion transverse to the flow.
VIV OF A CYLINDER IN FLUID FLOW
HOW FISHES SWIM IN
WATER
VORTEX INDUCED VIBRATIONS AQUATIC CLEAN ENERGY -VIVACE
• Entails a cylinder that hangs horizontally across the flow of water.
• The cylinders are free to move through the guide ways in the vertical direction
• The cylinder holds a magnet at the end, inside the guide ways.
• A metal coil winding is provided inside the guide ways
CONSTRUCTION
PARTS
HOW THE VIVACE WORKS
THE CONVENTIONAL WIND TURBINE`
• The flow of air across the blades creates lift that turns the rotor of a wind turbine.
• The world’s largest wind farm, the Horse Hollow Wind Energy Center in Texas, generates 735.5 MW at peak power with 291 1.5 MW wind turbines and 130 2.3 MW wind turbines spread over an area of 190 square kilometers.
• The rated wind speed required for this output is 12m/s• The farm occupies a volume of almost 22 cubic
kilometers.
WHY THE VIVACE? Water has a high energy density and is 830 times
denser than air.
The comparable water flow velocity to air velocity of 12m/s is 1.3 m/second.
The Corresponding power density is 185 watts per cubic meter.
The power density of the VIVACE converter is
14,600 times greater than that of the wind farm. Power is generated at a cost of
2.45 RS/KWH
TECHNOLOGY CAPITAL COSTRS/kW
FUEL COSTRS/kWh
CAPACITY FACTOR (%)
COST RS/ kWh
Conventional Generation
PULVARISED COAL 64,664 .495 85% 1.845
NUCLEAR 98,100 .225 90% 2.07
NATURAL GAS 21,015 1.935 45% 2.79
Alternative Generation
WIND 54,000 0.000 25% 3.105
VIVACE 135,000 0.000 90% 2.475
SALIENT FEATURES
• CLEAN ENERGY• DOESN’T DISRUPT THE NATURAL FLORA & FAUNA• NO DAMS OR TURBINES ARE USED• POWER AT 2.75 RS/KWh• CONSISTANT AND RELIABLE POWER GENERATION
THROUGHT THE YEAR.• GENERATES POWER IN WATER CURRENTS OF EVEN 1 KNOTS
(I KNOT=1.85Km/hr)
ADVANTAGES
Has high energy density Is unobtrusive to navigation Is unobtrusive to coastal property Is unobtrusive to marine life Has good robustness Has low maintenance Achieves certain life cycle cost target Have a design life of at least 15-20 years
REFERENCES• ASME JOURNAL (mechanical engineering) - APRIL 2010• www.vortexhydroenergy.com• www.asme.org/vivaceconverter• www.rexresearch.com/bernitsas/bernitsas.htm• www.techtransfer.umich.edu• www.renewableenergyworld.com• memagazine.asme.org/Articles/2010/April/
Out_Vortex.cfm
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